Images showing how the city state's Jewel Changi Airport will look when it's finished were released as construction got underway this month.

They show impressive steel-and-glass biosphere-style structures filled with plants and a gigantic waterfall.

If the finished product -- scheduled for completion in 2018 -- matches the proposals, it's likely to cement Changi's reputation as one of the world's favorite airports and a destination in its own right.

The massive donut-like structure at its core will be 10 stories -- five above ground and five underground -- integrating airport facilities, with retail and leisure outlets.

There'll also be playgrounds and a hotel.

More than simply a new terminal, Jewel Changi Airport will be constructed on the site of the old parking lot fronting the existing Changi Airport's Terminal 1, and will be "seamlessly connected" to the existing terminals, according to the airport.

Bringing nature indoors ... really

Maintaining Singapore's reputation as the "garden city," Jewel Changi's centerpiece will be Forest Valley, a five-story garden with thousands of trees, ferns and shrubs.

Commuters will even be able to take a hike up the valley.

"We wanted to create a space where activities that were traditionally outdoors in nature are brought to an indoor environment," Robin Goh, Changi Airport Group spokesperson, tells CNN.

Overnighting at the airport? This should cheer you up.

Cascading through Jewel's donut hole, in the middle of the forest, will be the 40-meter-high Rain Vortex.

On completion, it'll be the world's tallest indoor waterfall, according to the airport.

At night, the Rain Vortex will transform into a light and sound show.

Four different gateway gardens will feature unique landscape elements.

The North Gateway Garden, for instance, will use the trunks of rain trees recycled from the airport's old open-air parking lot.

On the top level, Canopy Park will have gardens, walking trails, playgrounds and eateries spanning approximately 13,000 square meters.

"We envisaged an area that comes with big sprawling spaces and play activities," says Goh of Canopy Park.

"We wanted to create a place where visitors can simply relax and have fun with their families and friends."

Staying ahead of the field

Travelers will be able to stay at Jewel's own hotel -- approximately 130 rooms operated by international hotel brand YOTEL.

The complex will house an "integrated multi-modal transport lounge."

That means ticketing, boarding pass and baggage transfer service will be available for passengers.

Early check-in facilities at the complex will allow passengers to check-in and drop off luggage ahead of regular check-in times.

Looking like green-jelly doughnut, Jewel Changi Airport will be a destination in itself when completed.

There'll also be new subway links connecting all the airports terminals to the MRT network.

A winner of multiple best airport awards over the years, Changi served 53.7 million passengers in 2013.

The airport expects a new Terminal 4 opening in 2017 for Cathay Pacific and Jewel in 2018 to bring 85 million passengers a year.

"In order for Changi Airport to stay ahead amidst intensifying competition from other airports, it's important for continuous innovation to be introduced," says Goh.